Ram & Jeep: Lightweight designs go mainstream

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Ram & Jeep: Lightweight designs go mainstream

Two of FCA’s most popular vehicles feature advanced lightweight materials strategies, mixing aluminum and steel components to boost efficiency and performance.

Robert Schoenberger

When you design a new vehicle from scratch, it’s easy to think big – push the limits of performance and fuel efficiency, explore radical designs that will excite and challenge buyers, integrate every electronic bell and whistle you can imagine.

However, when you’re working on vehicles with decades of history, loyal fans, and billions of dollars invested in manufacturing capacity, things get much tougher. On one hand, staying competitive means changing as much as possible. On the other, change too much, and you risk customer loyalty and corporate profits.

2018 Jeep Wrangler

200 lb lighter than 2017 model

Aluminum doors, liftgate, fenders

44° approach angle, 27.8° breakover angle, 37 °departure angle

Up to 30” water fording

3,500 lb tow capacity

That’s been the challenge for Fiat Chrysler Automobiles’ (FCA’s) most important vehicles. In the past 18 months, the automaker has massively reimagined its iconic Jeep Wrangler, a vehicle with more than 75 years of heritage, and its Ram 1500 pickup, the best-selling model for the entire company. The new vehicles are lighter and more efficient than the models they replace, yet they retain the elements needed to keep buyers, corporate cost managers, and regulators happy.

“We are the stewards of a brand that owes everything to the enthusiasm of the Jeep community,” says Mike Manley, FCA’s recently named CEO and the former head of the Jeep and Ram brands. “Our job is to listen and deliver on what they so clearly want.”

Both vehicles show what manufacturing technology is enabling in modern production. Better machining techniques support higher performance engines, better understandings of materials allow the combination of aluminum and steel to lower weights, and better simulation and visualization software have provided designers more freedom to imagine the future of transportation. That’s why GIE Media chose FCA’s two most iconic vehicles to showcase at IMTS 2018 in Booth #236900.

2018 Jeep Wrangler

Making a pickup or off-road vehicle that gets 30mpg is deceptively easy. Throw in a 66hp, 1.3L, 4-cylinder engine; replace heavy-duty frame components with less-capable ones; and avoid four-wheel drive systems and their heavy transfer cases. That was the thinking behind the 1986 Suzuki Samurai, a vehicle that looked a lot like the Jeep CJ7 on sale more than 30 years ago.

But it wasn’t a Jeep.

It couldn’t splash through steams, power up hills, or ignore major obstacles in its path. Every component that makes a Jeep Wrangler heavy is what makes it the most dominant off-road vehicle in U.S. history. So, when FCA officials tasked the Wrangler design team with lowering weight and improving fuel efficiency for the 2018 Wrangler, the simple, easy options were off the table.

“The all-new Wrangler is instantly recognizable as a Jeep, staying true to the original, yet it is better in every way – delivering even more rugged capability, more ride comfort, more fuel efficiency courtesy of several advanced powertrain options, more interior comfort, more safety, and more technology,” Manley says.

Designers working on the 2018 model knew they couldn’t lower power, remove rugged-but-heavy suspension components, or eliminate four-wheel drive systems. The new Wrangler would need a stiff, rugged, steel frame under its body.

Some clever engine technologies (a turbocharged 4-cylinder option or a V-6 with start-stop technology that shuts off the engine at stop lights to conserve gas) and a more-efficient transmission would help, but those improvements wouldn’t offer the efficiencies needed to comply with future fuel-economy regulations or help the vehicle’s popularity grow in countries with high fuel costs.

“With the lighter panels, we only need one bolt per hinge on the doors and liftgate,” Gale says. “So, it’s much easier to remove those for off-roading. We only needed four bolts to lower the windscreen from the safety frame.”

2019 Ram 1500

While pickup drivers don’t want to waste gasoline, fuel economy tends to be a secondary concern to performance. So, improved efficiency for FCA’s best-selling vehicle couldn’t come at the expense of power, towing capacity, or seating space. As with the Jeep, strategic use of advanced materials lowered weight by 225 lb compared to the outgoing model.

The Ram’s chassis is 120 lb lighter than the outgoing model – 100 lb from the frame, 20 lb from the suspension. Nearly all the frame’s material (98%) is high-strength steel. Automakers increase their use of stronger, stiffer steel each year to cut weight by replacing thicker components with hard-to-cut, and hard-to-form, thin-walled replacements.

2019 Ram 1500 Laramie

Ram 1500 hoods have been aluminum for several years, but for the 2019 model, the company also used the lightweight metal for the tailgate, engine mounts, front-axle center section, front-suspension crossmember, transmission crossmember, and steering system gear.

Mixing metals lowers weight, but the process requires upgraded paint pre-treatment systems, investments in joining systems, and higher material costs. Joe Dehner, head of Ram and Mopar design at FCA, says those changes were needed to meet the company’s “no sacrifices” goal for the truck.

“Cutting weight and boosting efficiency are easy if you’re willing to ask your customers to accept less or pay more. It’s a lot harder when you don’t want them to have to deal with the tradeoffs,” Dehner says.

2019 Ram 1500 with 5.7L Hemi V-8 engine

To further cut weight, engineers replaced steel upper front suspension control arms (integrated with a steel structure) and air-dam structures with composite versions.

One issue designers ran into during the redesign, he says, was increased noise in the truck’s cabin when equipped with the company’s popular 5.7L Hemi V-8 engine. Adding insulation or thicker materials deadens noise but adds weight. Instead, the team added electronically controlled, side-frame-mounted, active tuned-mass modules (ATMM) that work with an interior active noise cancellation (ANC) system Hemi-equipped models. The system reduces ambient sounds down to a low 67.1dB, making the new model the quietest Ram 1500 ever.

About the author: Robert Schoenberger is the editor of TMV and can be reached at 216.393.0271 or rschoenberger@gie.net.

1942 Willys-Overland Jeep2018 Jeep Wrangler1994 Wrangler1955 CJ-5

Jeep: 78 years of off-road dominance

1940: U.S. Army requests proposals from automakers for a light reconnaissance vehicle to replace aging Ford Model T trucks – initial specs called for less than 1,300 lb vehicle weight, up to 50mph capability; all prototype vehicles exceed weight limits; Willys-Overland wins the military contact

1940: Willys MA/MB vehicles quickly become known as jeeps – opinions differ if name comes from Army acronym GP for general purpose or from Eugene the Jeep character from Popeye cartoons; 2,560 lb weight exceeds updated Army specs; Willys-Overland and Ford Motor Co. (under license) produce nearly 650,000 Jeeps during World War II for military use

1945: Willys CJ-2A Jeep becomes first version available to consumers; features not included on military versions include larger headlights, external fuel caps, tailgates; 2.2L 4-cylinder engine standard

1953: The Kaiser Co. buys Willys-Overland, including the third generation of the consumer Jeep, the CJ-3B